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  <div class="section" id="match">
<h1>match<a class="headerlink" href="#match" title="Permalink to this headline">¶</a></h1>
<div class="section" id="header">
<h2>Header<a class="headerlink" href="#header" title="Permalink to this headline">¶</a></h2>
<div class="highlight-cpp"><div class="highlight"><pre><span></span><span class="cp">#include</span> <span class="cpf">&lt;boost/hof/match.hpp&gt;</span><span class="cp"></span>
</pre></div>
</div>
</div>
<div class="section" id="description">
<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline">¶</a></h2>
<p>The <code class="docutils literal"><span class="pre">match</span></code> function adaptor combines several functions together and
resolves which one should be called by using C++ overload resolution. This
is different than the <code class="docutils literal"><span class="pre">first_of</span></code> adaptor which resolves
them based on order.</p>
</div>
<div class="section" id="synopsis">
<h2>Synopsis<a class="headerlink" href="#synopsis" title="Permalink to this headline">¶</a></h2>
<div class="highlight-cpp"><div class="highlight"><pre><span></span><span class="k">template</span><span class="o">&lt;</span><span class="n">class</span><span class="p">...</span> <span class="n">Fs</span><span class="o">&gt;</span>
<span class="k">constexpr</span> <span class="n">match_adaptor</span><span class="o">&lt;</span><span class="n">Fs</span><span class="p">...</span><span class="o">&gt;</span> <span class="n">match</span><span class="p">(</span><span class="n">Fs</span><span class="p">...</span><span class="n">fs</span><span class="p">);</span>
</pre></div>
</div>
</div>
<div class="section" id="requirements">
<h2>Requirements<a class="headerlink" href="#requirements" title="Permalink to this headline">¶</a></h2>
<p>Fs must be:</p>
<ul class="simple">
<li><a class="reference internal" href="../../../doc/src/concepts.html#constinvocable"><span class="std std-ref">ConstInvocable</span></a></li>
<li>MoveConstructible</li>
</ul>
</div>
<div class="section" id="example">
<h2>Example<a class="headerlink" href="#example" title="Permalink to this headline">¶</a></h2>
<div class="highlight-cpp"><div class="highlight"><pre><span></span><span class="cp">#include</span> <span class="cpf">&lt;boost/hof.hpp&gt;</span><span class="cp"></span>
<span class="k">using</span> <span class="k">namespace</span> <span class="n">boost</span><span class="o">::</span><span class="n">hof</span><span class="p">;</span>

<span class="k">struct</span> <span class="n">int_class</span>
<span class="p">{</span>
    <span class="kt">int</span> <span class="k">operator</span><span class="p">()(</span><span class="kt">int</span><span class="p">)</span> <span class="k">const</span>
    <span class="p">{</span>
        <span class="k">return</span> <span class="mi">1</span><span class="p">;</span>
    <span class="p">}</span>
<span class="p">};</span>

<span class="k">struct</span> <span class="n">foo</span>
<span class="p">{};</span>

<span class="k">struct</span> <span class="n">foo_class</span>
<span class="p">{</span>
    <span class="n">foo</span> <span class="k">operator</span><span class="p">()(</span><span class="n">foo</span><span class="p">)</span> <span class="k">const</span>
    <span class="p">{</span>
        <span class="k">return</span> <span class="n">foo</span><span class="p">();</span>
    <span class="p">}</span>
<span class="p">};</span>

<span class="k">typedef</span> <span class="n">match_adaptor</span><span class="o">&lt;</span><span class="n">int_class</span><span class="p">,</span> <span class="n">foo_class</span><span class="o">&gt;</span> <span class="n">fun</span><span class="p">;</span>

<span class="k">static_assert</span><span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">is_same</span><span class="o">&lt;</span><span class="kt">int</span><span class="p">,</span> <span class="k">decltype</span><span class="p">(</span><span class="n">fun</span><span class="p">()(</span><span class="mi">1</span><span class="p">))</span><span class="o">&gt;::</span><span class="n">value</span><span class="p">,</span> <span class="s">&quot;Failed match&quot;</span><span class="p">);</span>
<span class="k">static_assert</span><span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">is_same</span><span class="o">&lt;</span><span class="n">foo</span><span class="p">,</span> <span class="k">decltype</span><span class="p">(</span><span class="n">fun</span><span class="p">()(</span><span class="n">foo</span><span class="p">()))</span><span class="o">&gt;::</span><span class="n">value</span><span class="p">,</span> <span class="s">&quot;Failed match&quot;</span><span class="p">);</span>

<span class="kt">int</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{}</span>
</pre></div>
</div>
</div>
<div class="section" id="references">
<h2>References<a class="headerlink" href="#references" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li><a class="reference external" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0051r2.pdf">POO51</a> - Proposal for C++
Proposal for C++ generic overload function</li>
</ul>
</div>
</div>


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